RAPID: Impacts of Hurricane Maria on tropical forest biogeochemistry: short-term response and long-term trajectory

这项研究将研究飓风玛丽亚对热带森林有机碳和营养物质动态的直接影响，以及排水森林的溪流，以更好地确定短期影响如何影响森林和水资源在单次和反复干扰后的长期轨迹。飓风玛丽亚导致波多黎各Luquillo实验森林（LEF）的冠层大面积破坏和土壤表面和河道中的凋落物沉积。了解植物碎屑中的有机碳、磷和氮在通过土壤进入河流的过程中是如何被改变的，包括与大气的任何交换，对于确定生态系统对干扰的长期反应至关重要。作为该项目的一部分进行的研究将提供对LEF生态系统（美国国家森林系统中El Yunque国家森林的一部分）的恢复力和抵抗力的见解。PI团队将与波多黎各的科学家和学生密切合作，促进当地学生和教师的研究需求。研究人员将把这个项目的结果建立在一个以气候变化对陆地生态系统的影响为中心的报告和推广活动的组合中。该项目将通过支持波多黎各学生成为实验室人员、向其他西班牙裔学生和博士后科学家提供培训以及通过外联和指导活动促进科学领域的性别平等，促进科学领域的多样性。这项研究利用了一个预先存在的飓风模拟实验，允许研究人员测试关于单次和多次飓风干扰对生态系统过程的影响的假设，包括通过土壤剖面和微生物活动响应基质可用性和湿度条件的碳和营养物质的生物地球化学易位。研究小组将量化土壤上的凋落物数量，测量土壤剖面、土壤溶渗仪和溪水中的土壤碳、磷组分、氮矿化、铁、铝和pH值。微生物活性将被评估，同时也针对与大分子碳水化合物降解和氮磷循环相关的基因表达。通过Illumina HiSeq测序的转录数据将映射到预先存在的宏基因组组装的支架上，并提供一种评估基因表达变化的方法。该研究将提供第一个飓风影响的综合实验，该实验将描述前后环境条件和生物地球化学循环与土壤深度的关系，以及单次和反复扰动的关系。这个小组也将是第一个采用新的微生物活性分析，转录组学，并将其与干扰和恢复背景下的生物地球化学指数直接联系起来的小组。

This research will study the immediate effects of Hurricane Maria on the dynamics of organic carbon and nutrients in a tropical forest and the streams draining that forest to better determine how short-term impacts affect the long-term trajectory of forest and water resources following single and repeated disturbances. Hurricane Maria led to widespread canopy damage and litter deposition on the soil surface and in stream channels within the Luquillo Experimental Forest (LEF) in Puerto Rico. Understanding how organic carbon, phosphorus, and nitrogen within plant detritus are modified during their movement through soils and into streams, including any exchanges with the atmosphere, is critical to determining long-term ecosystem response to disturbance. The research conducted as part of this project will provide insights into the resilience and resistance of the LEF ecosystem, part of the El Yunque National Forest in the US National Forest System. The PI team will work closely with scientists and students in Puerto Rico and facilitate local student and faculty research needs. The investigators will build the project results into a portfolio of presentations and outreach activities centered on the impacts of climate variability on terrestrial ecosystems. The project will promote diversity in science by supporting Puerto Rican students as laboratory personnel, providing training to other Hispanic students and post-doctoral scientists, and promoting gender equity in science through outreach and mentoring activities.This research makes use of a pre-existing hurricane simulation experiment allowing the researchers to test hypotheses about the effects of single and repeated hurricane disturbance on ecosystem processes, including biogeochemical translocations of carbon and nutrients through soil profiles and microbial activities in response to substrate availability and moisture conditions. The research team will quantify the amount of litter deposited on the soil, measure soil carbon and phosphorus fractions, nitrogen mineralization, iron species, aluminum, and pH in soil profiles, soil lysimeters, and stream water. Microbial activity will be assessed while also targeting gene expression related to macromolecular carbohydrate degradation and nitrogen and phosphorus cycling. Transcript data sequenced via Illumina HiSeq will be mapped to assembled scaffolds from pre-existing metagenomes and provide a means of assessing changes in gene expression. The research will provide the first comprehensive experiment of hurricane effects that characterizes the pre- and post-environmental conditions and biogeochemical cycling with soil depth, and across single and repeated disturbances. This group will also be the first to employ novel analyses of microbial activity, transcriptomics, and link this directly with biogeochemical indices in the context of disturbance and recovery.